MEASURING DIETARY FIBER

这项拟议研究的长期目标是阐明 膳食纤维的作用机制。有些是结果 它存在于肠道中；其他的无疑是其 新陈代谢，主要发生在大肠通过 微生物区系的作用。然而，微生物的活性将取决于 在可用的底物上。纤维对小肠的影响 消化酶活性，腔内容物的粘度， 转运速度和粘蛋白分泌都会影响底物。 可用于发酵。此应用程序的主要目标是 研究膳食纤维代谢的性质和程度 胃肠道中的其他底物，并开始检查 从这些底物中释放的能量的分布 细菌和短链脂肪酸之间。方法，以 描述膳食纤维并将其与其他 肠腔内容物中的多糖来源，即细菌， 粘蛋白和未消化的食物碳水化合物是主要关注的焦点 我们的研究。这些方法将用于确定 用食用菌采集的消化液分析膳食纤维的代谢 清醒的小型猪通过外科手术在不同部位植入插管 位于胃肠道的部位。底物比例 用于细菌生长和新陈代谢的将由 测定细菌质量和消化液消失率。能量 将通过测量短链来评估可吸收的能力 在体外孵化消化过程中产生的脂肪酸。我们 假设可溶纤维和粘蛋白将迅速 在近端的结肠中发酵，这种不溶性纤维将被 主要在远端结肠代谢。这项研究将 解决几个重大的人类健康问题，包括 充足的膳食纤维在治疗肥胖症和糖尿病中的作用 糖尿病和动脉粥样硬化形成过程中。这项研究还 将通过以下方式检验纤维影响结肠癌发生的假说 部分地通过改变底物来改变微生物的代谢 可用于发酵。

The longterm goal of the proposed research is to elucidate the mechanisms of action of dietary fiber. Some are a consequence of its presence in the gut; others are undoubtedly a result of its metabolism, which occurs principally in the large bowel through the action of microflora. Microbial activity will, however, depend upon the substrates available. The effects of fiber on small bowel digestive enzyme activities, the viscosity of the lumenal contents, the rate of transit and mucin secretion all influence the substrate available for fermentation. The primary aim of this application is to study the nature and extent of metabolism of dietary fiber and other substrates in the gastrointestinal tract and begin to examine the distribution of the energy released from these substrates between bacteria and short chain fatty acids. Methods to characterize dietary fiber and to distinguish it from other polysaccharide sources in gut lumenal contents, i.e. bacteria, mucins and undigested food carbohydrate, are a major focus of our research. These methods will be used to determine the metabolism of dietary fiber by analyzing digesta collected from conscious minipigs with cannulas surgically implanted at different sites in the gastrointestinal tract. The proportion of substrate used for bacterial growth and metabolism will be evaluated by measuring bacterial mass and disappearance of digesta. Energy available for absorption will be assessed by measuring short chain fatty acids produced during in vitro incubation of digesta. We hypothesize that soluble fibers and mucin will be rapidly fermented in the proximal colon and that insoluble fiber will be metabolized principally in the distal colon. This study will address several significant human health issues, including the role of adequate dietary fiber in the treatment of obesity and diabetes mellitus and in the process of atherogenesis. This research also will test the hypothesis that fiber affects colon carcinogenesis by modifying microbial metabolism, in part, by altering the substrate available for fermentation.